Aircraft propeller



M U R D N A L P AIRCRAFT PROPELLER Filed April 22, 1937 3 Sheets-Sheet 1 II ll INVENTOR PargerLamdrum M H II ATTORNEY M U R D N A L P AIRCRAFT PROPELLER Filed April 22, 1937 3 Sheets-Sheet 2 INVENTOR Paw/Land? 'ATTORNE Patented June 25, 1940 UNITED STATES PATENT OFFICE I AIRCRAFT Porter Iandrum,

Application April 22,

GClaims.

My invention-relates to aircraft propellers and more particularly concerns the' type oi. propeller which is provided with blades adiustably mounted on the hub of the propeller and adaptedto be regulated to suit various flying conditions.

My invention further contemplates the provision of a propeller embodying means for changing the pitch of the blades. 1

My invention further contemplates the provision of a propeller having means for moving the propeller blades radially for increasing or decreasing the diameter of the propeller.

,My invention further contemplates the provision of hydraulic means for decreasing the diameter of the propeller and manual and auto- -matie means for controlling the movement ofthe propeller blades.

Briefly, my invention comprises a propeller hub having cylinders i'ormed therein to receive the piston-shaped ends of the propeller blades. A pair of pumps are mounted on the hub of the propeller and are adapted to .be either manually or automatically entered into engagement with a cam for forcing liquid into the cylinders to decrease the ,diameter of the propeller. Valve means are provided for draining the liquid from the cylinders to increase the diameter of the propeller and means are provided for equalizing the movement of the propeller bladesr An arm an is provided for engagement with each propeller blade and adjustably connected to the hub of the panying drawings, forming part thereof, where- Fig. 1 is a plan view of my improved propeller,

showing the propeller bladesin their outer position;

Fig. 2 is a sectional view taken along the line II-II of Fig. 3, showing the propeller blades in their outer position and a rather diagrammatic illustration of the pumps, valves, and conduits employed for increasing and decreasing the diameter of the propeller;

Fig. 3 is a sectional view taken along the line IIIIII of Fig. l,- showing the pumps in position to be actuated by the cams to direct liquid "through the valves and conduits for decreasing the diameter of the propeller;

Fig. 4 is a fragmentary sectional view showing a pump held out of engagement with its operating cam, and its control valve disposed to prevent the passage of liquid therethrough to maintain the blades of the propeller against movement;

Fig. 5 is a fragmentary view similar to Fig. 4 in which the pump is held out of engagement Paormna Birmingham, Ala. 1937, Serial No. 138,326 (Cl. -103) mit the liquid to flow from the blade cylinders back to the liquid reservoir thereby causing the blades to be moved outwardly by centrifugal force; and

Fig. 6' is a sectional view taken along the line VI--VI of Fig. 3, showing the equalizing mechanism for the propeller blades.

Referring now to the drawings for a better understanding of my invention I show a propeller comprising a housing 8 which is secured on the end of the propeller shaft 9 by means of splines ii and a nut i2. Cylinders it are formed in opposite ends of the housing to receive the piston shaped endsof the propeller blades i i and are provided with stuillng-boxes it to prevent leakage of liquid from the cylinders. The ends of the blades are flanged at it and provided with piston rings it for liquid-tight, frictional engagement with the cylinder walls.

The inner ends of the blades are hollow to re ceive the pitch changing sleeves is which are slotted at it to receive their respective cross pins .22 mounted in the blades. Each sleeve it is provided with an adjustment arm at which prowith its cam and the valve is positioned to perjects through an opening it in the housing for engagement with a boss it termed on the housing. The bosses 2% are slotted at ii to receive the bolts it for loom the adjustment a. A partition 29 is provided within each blade to prevent a flow of liquid into the ends of same.

A pair of pump cylinders at are formed in the housing on opposite sides of the propeller shaft to receive plungers 32 adapted to be forced inwardly of the cylinders by the cam surface dd formed on the cam sleeve til. e plungers are moved outwardly and held in operating cont with the cam surface by compron springs 3d. The cam sleeve is secured to the engine housing til.

A rotary control valve 88 is provided for h pump and controls the flow of liquid from the pump to the cylinders and from the cylinders to the reservoir. A passageway it leads from each pump to a port ti in the valve. A geway 42 leads from a port at in the valve to an equalizing passageway M and thence to the outer end of each cylinder, and a passageway 46 leads from the inner end of each cylinder to its respective pump.

A check valve W is interposed in each 0! the passageways 39, and a check valve 48 is placed in each of the passageways 46. A pair of valve and pump control mechanisms are provided, one on each side of the propeller shaft, and as they are identical in construction and operation only one shall be described. A rocker arm Si is pivotally mounted on the housing at 52 and has its outer and connected to a control rod 53 and its inner end connected to a plunger liit rod M with collars at for rotatable engagement with flanges 66 formed on the propeller blades. Rollers 61 are provided to serve as guides for the equalizing bars, and a plate 68 is slotted at 68 toserve as a guide for the end of the control rod h s. A cap I! is provided on the front of the housing to cover the end of the propeller shaft and the adjustment arms 23, and thrust bearings are interposed between the blade flanges it and the stuffting-boxes it. A control collar W2 is slidably mounted on the cam sleeve 34 and engages the ends of the plunger lift rods 54.

In the operation of my propeller to change its diameter, liquid is supplied from a suitable source through the passageway it in thepropeller shaft to the inside of the housing. When the blades it are in their outer position, they may be moved inwardly-by manually moving the control collar away from the housing to the position shown in Fig. 3, thereby causing the plungers to be actuated by cam surface 33 and bringing the ports ii and 59 into register with the passageways 39 and M, respectively.

When the propeller blades it have-been forced to their inner position by hydraulic pressure in cylinders i3, their movement is automatically stopped by means of the cam surfaces 58 on the equalizing bars 59 coming in contact with the rollers 5'! provided on the control rods 53. This movement of the control rods causes the valves 38 to rotate to their closed position, shown in Fig. 4, in which the passageways #32 are closed to hold the liquid within the cylinders l3. The control rods also cause the lift rods 56 to move the plungers 32 out of contact with the cam surface 33.

In order to return the propeller blades to their outer position, the control collar 82 is move outwardly to the position shown in Fig. 5. This causes the valves 38 to be rotated to bring the drainage ports it into registry with the passageways 42 and the drainage passageways ll which lead back to the housing 8 and thence to the reservoir.

It willbe seen that the propeller blades may readily be moved to and maintained in any position between their inner and outer positions and that automatic means may readily be employed for moving the control collar it for maintaining the propeller blades at their proper positions at all times. The pitch of the propeller blades may be adjusted by moving the adjustment arms 23,

and it will be seen that this may be accomplished by automatic means if desired as several devices now on the market may be applied thereto. The thrust bearings it are employed between the flanges H and K stufllng-boxes it when auto- .matic means are employed for changing the pitch .of the blades.

While I have shown my invention in but one form, it is obvious to those skilled in the art that it is not so limited but is susceptible of various changes and modifications without departing from the spirit thereof; and I desire, therefore, that only such limitations shall be-placed thereupon as are imposed by the prior art.

I claim:

1. In an aircraft propeller, a housing, cylinders formed in said housing, propeller blades having pistons formed on their inner ends and mounted for reciprocation within said cylinders, pump means for supplying liquid to the cylinders to move the propeller blades inwardly, valve means for controlling the flow of liquid to and from the cylinders, and means actuated by the movement of the propeller blades for operating the valve means to bring the propeller blades to rest.

2. In .an aircraft propeller, a housing, cylinders formed in said housing, propeller blades having pistons formed on their inner ends and mono d for reciprocation within said cylinders, pump means for supplying liquid to the cylinders to move the propeller blades inwardly, valve means for controlling the flow of liquid to and from the cylinders, and means actuated by the movement of the propeller blades for operating the valve means and the pump means to bring the propeller blades to rest. A

3. In an aircraft propeller, a housing, cylinders formed in said housing, propeller blades having pistons formed on their ends and mounted for reciprocation within said cylinders, equalizing members connecting the propeller blades {for equalizing their reciprocating movement, pump means for supplying liquid to the cylinders to move the propeller blades inwardly, valve means for controlling the flow of liquid to and from the cylinders, and means actuated by the equalizing members for operating the valve means to bring the propeller blades to rest at a predetermined position.

4. A device according to claim 3 in which, the equalizing members comprise'racks having their outer ends connected to the propeller blades and their inner ends engaging a common pinion mounted on the housing.

5. In an aircraft propeller, a housing, cylinders formed in said housing, propeller blades having pistons formed'on their ends and mounted for reciprocation within said cylinders, pump means mounted on the housing, valve means mounted on the housing, a liquid supply conduit leading from the inner ends of the cylinders to the pump means thence to the valve means and thence to the outer ends of the cylinders, a liquid outlet conduit leading from the valve means to the inner ends of the cylinders, and common means for operating the pump means and valve means to cause liquid to flow to and from the outer ends of the cylinders to vary the diameter of the propeller.

6. In an aircraftpropeller, a housing, cylinders formed in said housing, propeller blades having pistons formed on their ends and mounted for reciprocation within said cylinders, pump means mounted on the housing, valve means mounted on the housing, a liquid supply conduit leading from the inner ends of the cylinders to the pump means thence to the valve means and thence to the outer ends of'the cylinders, a. liquid outlet POR'I'ER LANDRUM. 

